Systematic Studies on Emission Quenching of Cadmium Telluride Nanoparticles

• Published in: Journal of physical chemistry. C Vol. 113; no. 52; pp. 21621 - 21628
• Main Authors: Uematsu, Taro, Waki, Takahiro, Torimoto, Tsukasa, Kuwabata, Susumu
• Format: Journal Article
• Language: English
• Published: American Chemical Society 31.12.2009
• Subjects: C: Nanops and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp908279k

Quenching of emissions from cadmium telluride (CdTe) nanoparticles was distinctly observed by the addition of various electrochemically active organic molecules. The quenching ability of organic molecules is greatly influenced not only by their valency and redox potential but also by a type of capping ligand and the particle size of the CdTe nanoparticles. These effects are systematically studied through the fluorescence intensity and its lifetime changes based on photoinduced electron transfer reactions. The results suggest the existence of two different quenching mechanisms: diffusion-mediated electron transfer and electrostatic adsorption of the quenchers, which are both dependent on the valency of the quenchers. Besides conventional reaction schemes such as Rehm−Weller-type photoinduced electron transfer, a new reaction scheme has been successfully introduced by considering multiple adsorption of organic quenchers on a semiconductor nanoparticle. In this scheme, the kinetics of the electron transfer reactions between nanoparticles and quenchers became observable by emission quenching experiments, and they have been studied on the basis of Marcus theory.